having a durable frame on your bike provides the central core for your entire motorcycles performance ability and general set-up. the motorcycle frame provides the necessary structure for holding and maintaining braking and all handling factors. the motorcycle frame and all its many accessories contain the suspension and acts as an engine casing. the motorcycle frame is a fixed structure- not containing joints, that connects steering and the swing-arm. frame designs vary between different kinds of motorcycles. the hard tail for example has no rear suspension.